Deaf children are often assumed to be a homogeneous group with the same language development issues. This is incorrect, many different groups exist.

Within sign language, deaf children of deaf parents (native signers) have been found to significantly perform better than late signers (deaf children of hearing parents who cannot sign or have limited skills) in several aspects of the cognitive domain.

Two tasks will be discussed in this talk: Theory of Mind and Referential Communication. The development of a British Sign Language version of the MacArthur-Bates Communicative Development Inventory will then be discussed with insights into optimal and natural language growth in children of Deaf parents, both deaf and hearing.